Prostate radiotherapy apparatus

ABSTRACT

Radiotherapy apparatus including a first probe insertable into a first body cavity, a second probe insertable into a second body cavity, and an external frame attached to the first and the second probes, such that the first and the second probes are in a fixed, known spatial relationship with respect to the external frame.

FIELD OF THE INVENTION

The present invention relates to prostate radiotherapy generally, andparticularly to apparatus for spatially fixing a target volume in aprostate which is to be irradiated.

BACKGROUND OF THE INVENTION

The use of radiotherapy to render tissue necrotic is well established,especially in treatment of tumors. A target volume in the tissue isirradiated at a multiplicity of orientations with finely collimatedbeams. A particular form of radiotherapy, called stereotacticradiotherapy, requires precise localization and fixation of the targettissue. It is essential to rigidly fix the target volume in space inorder to ensure that the radiation beams are correctly directed to thetarget. However, it is difficult, impractical and sometimes impossibleto rigidly fix some limbs in the human body sufficiently for precisestereotactic radiotherapy. The head is basically the only human organwherein the bone is so close to the skin and accessible so as to permitrigorously spatially fixing the cranium to a stereotactic frame.

It is readily understood that it is quite desirable to rigidly fix otherorgans, such as the prostate, to permit stereotactic radiotherapy.However, the prior art does not have any method or apparatus forspatially fixing the prostate.

SUMMARY OF THE INVENTION

The present invention seeks to provide apparatus for spatially fixing atarget volume in a prostate which is to be irradiated. The presentinvention also provides safety features such as injection of water inthe area of Denonvilliers' fascia for reflecting the rectal wall awayfrom the prostate and provision of cooling in the area of the prostateto reduce the adverse effects of radiation on healthy tissue, e.g., therectal wall or urethra.

Although the present invention will be described herein with referenceto prostate radiotherapy, it is understood that the present invention isapplicable to radiotherapy of other organs in males or females whereintwo probes can be inserted into the body for fixing therein an organ forstereotactic radiotherapy.

There is thus provided in accordance with a preferred embodiment of thepresent invention radiotherapy apparatus including a first probeinsertable into a first body cavity, a second probe insertable into asecond body cavity, and an external frame attached to the first and thesecond probes, such that the first and the second probes are in a fixed,known spatial relationship with respect to the external frame.

In accordance with a preferred embodiment of the present invention thefirst probe includes a urethral probe insertable into a urethra and thesecond probe includes a rectal probe insertable into a rectum.

Further in accordance with a preferred embodiment of the presentinvention the radiotherapy apparatus includes a source of radiationwhich produces a radiation beam, having a fixed, known spatialrelationship with respect to the external frame, that irradiates atarget substantially spatially fixed by the first and the second probes.

Still further in accordance with a preferred embodiment of the presentinvention the radiation beam exits a distal end of at least one of thefirst probe and the second probe. The radiation may be infrared (IR)radiation, microwave radiation, gamma ray radiation, or radio frequency(RF) electrical energy.

Additionally in accordance with a preferred embodiment of the presentinvention the radiotherapy apparatus includes adjustment apparatus thatadjusts the spatial relationship of the first and the second probes withrespect to the external frame.

Further in accordance with a preferred embodiment of the presentinvention the radiotherapy apparatus includes a beam controller forcontrolling an intensity of the radiation beam.

Additionally in accordance with a preferred embodiment of the presentinvention the radiotherapy apparatus includes imaging apparatus thatdetermines a position of the target with reference to the externalframe.

In accordance with a preferred embodiment of the present inventionimaging energy of the imaging apparatus is directed through a distal endof at least one of the first probe and the second probe. The imagingapparatus may comprise ultrasound apparatus.

Further in accordance with a preferred embodiment of the presentinvention the radiotherapy apparatus includes cooling apparatus thatcools tissue adjacent to at least one of the first probe and the secondprobe.

In accordance with a preferred embodiment of the present invention atleast one of the first and the second probes comprises an electrode fordelivering electrical current.

Further in accordance with a preferred embodiment of the presentinvention there is provided injection apparatus for injecting a fluid inthe vicinity of Denonvilliers' fascia to reflect a rectal wall from aprostate.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawing in which:

FIG. 1 is a simplified pictorial illustration of radiotherapy apparatusconstructed and operative in accordance with a preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIG. 1 which illustrates radiotherapy apparatus10 constructed and operative in accordance with a preferred embodimentof the present invention.

Radiotherapy apparatus 10 includes a first probe 12 insertable into afirst body cavity 14, and a second probe 16 insertable into a secondbody cavity 18. As mentioned above, the present invention is describedherein with reference to prostate radiotherapy, and thus first probe 12is herein referred to as a urethral probe 12 and first body cavity 14 isreferred to as a urethra 14. Second probe 16 is herein referred to as arectal probe 16 and second body cavity 18 is referred to as a rectum 18.

An external frame 20 is attached to urethral probe 12 and rectal probe16, such that probes 12 and 16 are in a fixed spatial relationship withrespect to external frame 20. External frame 20 preferably includesadjustment apparatus 22 that adjusts the spatial relationship ofurethral probe 12 and rectal probe 16 with respect to external frame 20.For example, adjustment apparatus 22 may include a slidable, graduatedrod 24 that is attached to urethral probe 12 and an adjustment knob 26.Rod 24 may be lowered or raised generally along an axis 29 and tightenedat a fixed position by means of knob 26.

A source 30 of radiation, such as infrared (IR) radiation, microwaveradiation, gamma ray radiation, radio frequency (RF) electrical energy,depending on the type of therapy, for example, produces a radiation beam27 that irradiates a target 28, such as a prostate. In one preferredembodiment, source 30 is an external source fixed relative to externalframe 20. Alternatively, radiation beam 27 may be suitably guided toexit a distal end of either one of the probes 12 or 16. In any case,radiation beam 27 has a fixed, known spatial relationship with respectto external frame 20, and radiation beam 27 irradiates target 28 whichis substantially spatially fixed by probes 12 and 16. A beam controller32 is preferably provided for controlling an intensity of radiation beam27.

In accordance with another preferred embodiment of the present inventionone or both of probes 12 and 16 comprises an electrode for deliveringelectrical current to target 28.

Imaging apparatus 34 is preferably provided for producing an image oftarget 28 and for tracking and monitoring the progress of the treatmentprocedure. Imaging apparatus 34 determines the position of target 28with reference to external frame 20 so that radiation beam 27, whoseposition is also fixed relative to external frame 20, may be accuratelyaimed at target 28. Imaging apparatus 34 may be a fluoroscope, X-raymachine or ultrasound imaging equipment, for example. In one preferredembodiment, imaging apparatus 34 is located externally to probes 12 and16. Alternatively, imaging energy of imaging apparatus 34 may bedirected through the distal ends of either or both probes 12 and 16.

Cooling apparatus 36 is preferably provided for cooling one or bothprobes 12 and 16. Cooling apparatus 36 may include cooling coils thattransport a refrigerant fluid along a length of the probes.Alternatively, cooling apparatus 36 may include thermoelectric coolersthat work on the Peltier effect, such as units commercially availablefrom Melcor, Inc. USA. The provision of cooling apparatus 36 isparticularly important if radiation beam 27 is transmitted through oneof probes 12 or 16, since the radiation beam tends to heat the areathrough which it passes, and this heat may be detrimental to delicatehealthy tissues in the vicinity of the probes.

As an added safety feature, injection apparatus 38 may be provided forinjecting a fluid, such as water, through the perineum to the vicinityof Denonvilliers' fascia, reference numeral 40, to reflect the rectalwall from the prostate. It is believed that the fluid does not affectthe spatial fixation of the prostate by probes 12 and 16.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the features describedhereinabove as well as modifications and variations thereof which wouldoccur to a person of skill in the art upon reading the foregoingdescription and which are not in the prior art.

What is claimed is:
 1. Radiotherapy apparatus comprising: a first probeinsertable into a first body cavity; a second probe insertable into asecond body cavity; an external frame attached to said first and saidsecond probes, such that said first and said second probes are in afixed, known spatial relationship with respect to said external frameand maintain a target organ in a fixed, known spatial relationship withrespect to said external frame; and a source of radiation fixed withrespect to said external frame and which produces a radiation beamdirected to said target organ.
 2. Radiotherapy apparatus according toclaim 1 wherein said first probe comprises a urethral probe insertableinto a urethra, and said second probe comprises a rectal probeinsertable into a rectum.
 3. Radiotherapy apparatus (10) according toclaim 1 and further comprising a source (30) of radiation which producesa radiation beam (27), having a fixed, known spatial relationship withrespect to said external frame (20), that irradiates a target (28)substantially spatially fixed by said first (12) and said second (16)probes.
 4. Radiotherapy apparatus according to claim 1 and wherein saidradiation beam exits a distal end of at least one of said first probeand said second probe.
 5. Radiotherapy apparatus according to claim 1and wherein said radiation is selected from the group consisting of:infrared (IR) radiation, microwave radiation, gamma ray radiation, andradio frequency (RF) electrical energy.
 6. Radiotherapy apparatusaccording to claim 1 and comprising adjustment apparatus that adjuststhe spatial relationship of said first and said second probes withrespect to said external frame.
 7. Radiotherapy apparatus according toclaim 1 and comprising a beam controller for controlling an intensity ofsaid radiation beam.
 8. Radiotherapy apparatus according to claim 1 andcomprising imaging apparatus that determines a position of said targetwith reference to said external frame.
 9. Radiotherapy apparatusaccording to claim 8 and wherein imaging energy of said imagingapparatus is directed through a distal end of at least one of said firstprobe and said second probe.
 10. Radiotherapy apparatus according toclaim 8 and wherein said imaging apparatus comprises ultrasoundapparatus.
 11. Radiotherapy apparatus according to claim 1 andcomprising cooling apparatus that cools tissue adjacent to at least oneof said first probe and said second probe.
 12. Radiotherapy apparatusaccording to claim 1 and wherein at least one of said first and saidsecond probes comprises an electrode for delivering electrical current.13. Radiotherapy apparatus according to claim 1 and comprising injectionapparatus for injecting a fluid in the vicinity of Denonvilliers' fasciato reflect a rectal wall from a prostate.